When my two dogs fight I can put my hands or face right between them without the slightest fear of being bitten.Let's assume that we are all in agreement that freedom from fear does not equate with actual safety. That aside, I interpret the sentiment to be one of "I know and trust my own dogs so well that normal safety measures do not apply in my interactions with them". While I can understand the sentiment on a certain level - after all, many of us feel that the bond we have with our dogs is special - I would offer that the feeling is misguided. It is perhaps akin to "I'm such a safe driver, I don't need to wear a seat belt".
Reality is comprised of each of our interpretations of life colliding. We think we can predict events based on past experiences or even a sense of faith. To some extent, this is not only possible but in fact useful. But nature - which includes animal behavior - has a way of upsetting the apple cart on a regular basis by reminding us of a basic truth: Life is uncertain.
Putting one's hands/face between two fighting dogs - regardless of any bond one feels with those dogs - is just bad judgment in my opinion. Humans may be top of the food chain but we can not control everything in life and certainly not dog behavior. For myself, I don't want to take too many chances - I've only got one pair of hands, one face and one, you know - life.